WHY A DRILL BIT “DOESN'T DRILL WELL” IN HARDWOOD (AND HOW TO GET THE BEST OUT OF IT)

Hardwoods such as beech, oak and many exotic timber species are among the most demanding materials to drill. It is common for users to describe a drill bit as "poor" because it burns the wood, cuts slowly or leaves an untidy hole. In most cases, however, the drill bit is not the problem. The real cause is usually a combination of the material, drilling technique and user expectations.

Not All Wood Is the Same

Hardwood has a dense structure and often contains mineral particles. This results in:

• higher drilling resistance
• greater heat generation
• faster tool wear

For this reason, hardwood does not behave like simply "harder softwood" during drilling—it requires a different approach.

How a Quality Wood Drill Bit Performs

Specialised wood drill bits, whether HSS or carbide-tipped, are designed differently from general-purpose drill bits such as those intended for metal.

• Centre point → accurate positioning
• Outer spurs → clean cutting of the wood fibres
• Cuts the fibres rather than forcing through the material

This produces clean, accurate holes, but these drill bits are also more sensitive to correct operating technique.

Important:

Basic wood drill bits made from chrome-vanadium steel (groups 4110 and 4120) are not suitable for hardwood. Their lower hardness causes the cutting edges to dull quickly under the higher drilling resistance and heat generated in hardwood. Once dull, the drill bit no longer cuts efficiently but instead rubs against the wood, which may cause burning or jamming.

For hardwood we recommend:

• HSS wood drill bits (group 4130)
• Carbide-tipped wood drill bits (group 4140)

The Most Common Problems When Drilling into Hardwood

The wood burns

Burning usually occurs when the drill speed is too high or the feed pressure is too low. Reduce the speed and apply slightly more pressure so the drill removes material smoothly.

The drill "doesn't bite"

This is most common with carbide-tipped drills. Carbide stays sharp longer than HSS but is not as aggressive. To drill effectively, apply a higher, steady feed pressure.

The hole splinters

Tear-out usually occurs on the exit side of the hole. Better results can be achieved by supporting the material from the back, drilling from both sides, or reducing the feed just before the drill breaks through.

The drill jams

This is usually caused by flutes clogged with chips. When drilling deeper holes, pull the drill out regularly and clean it so the chips can be removed efficiently.

HSS or Carbide – Which Drill Should You Choose?

Both drill types have their own advantages and limitations. The right choice depends on whether you prioritize a clean cut or long tool life.

Why an "Ordinary Drill Bit" Sometimes Seems Faster

Other drill bits (for example, metal drill bits) tend to force their way through the material rather than cleanly cutting the wood fibres.

The result:

• they may appear to "drill better"
• they damage the wood structure and produce lower-quality holes
• they generate more heat, increasing the risk of burning the wood
• they may become dull more quickly
• with larger diameters, they increase the risk of fibre tear-out and reduce drilling control

How to Drill Hardwood Correctly

Basic guidelines:

• reduce the spindle speed (compared with softwood)
• apply smooth, consistent feed pressure
• allow the drill bit to cut rather than rub
• clean the flutes regularly when drilling deeper holes
• support the workpiece to achieve a clean exit hole

A Simple Rule to Remember

Hardwood requires slower drilling speeds, lower spindle speeds and steady feed pressure. When these principles are followed, a quality drill bit will deliver the performance it was designed for.